Three league championships, one Scottish Cup and a last 16 Champions League appearance later, the 42-year-old has made more than a decent fist of his first attempt at being a boss.
However, for this relative rookie, the challenges continue to come thick and fast, both on and off the park.
And, while another league title is safely secured, along with the next crack at qualifying for the lucrative and increasingly essential Champions League, Lennon is having to deal with other issues which he would much rather do not darken his domain.
The weekend's 2-0 win over Dundee United hoisted his side out of their post-title-clinching-celebration mode and back into gear, the early goals from reinstated Georgios Samaras and in-form Anthony Stokes enough to take all three points from Tannadice.
Unfortunately, the performance was the meat in a Leigh Griffiths-controversy sandwich, the result of the striker's off-duty behaviour the previous weekend as he attended the Edinburgh derby with his Hibs cronies.
Lennon acted swiftly to lay down the law, fining Griffiths for singing a song about Hearts going bust, his performance captured on a camera phone and punted on to the world wide web, where, among others, SFA compliance oficer, Vincent Lunny, was able to view it.
A charge was soon winging its way to Griffiths via the club he joined only in January.
On Friday, Lennon made it clear he thought the matter had been dealt with internally, and explained that is why Celtic will defend Griffiths when his case is heard at Hampden in a couple of weeks.
But, given the nature of the additional footage which has been produced, in which Griffiths appears to be singing a racist song about former Hearts player, Rudi Skacel, will Celtic's support be removed?
And, given how clear Lennon was about Griffiths having been given his warning when the original offence had come to light, and that the player had to get the message or his career at the club wouldn't be as long as he would like it to be, has the manager painted himself into something of a corner?
Of course, the fact the two incidents happened at the same time - it was only their arrival in the public domain which had different dates - Lennon can consider it to be one and the same misdemeanour.
So, the one strike against Griffiths can be considered to cover both alleged offences, the route the SFA are expected to follow.
But it does not alter the fact that, if Lennon was annoyed at the behaviour of Griffiths when only aware of the the initial song, he is sure to be much nearer anger at the subsequent revelations.
Unless, that is, Griffiths came clean from the outset and forewarned Lennon there was worse to come, and that this was already taken into consideration by the Hoops boss.
The bottom line is that what Lennon definitely knew was the controversy already attached to Griffiths before he signed him - his off-field exploits making more headlines than anything he had ever done on the pitch - and there were plenty of people warning him off someone with so much baggage.
Lennon insisted from the outset he could handle him. So, he was aware he was putting his own reputation on the line.
Ten weeks later, he is entitled to feel badly let down by the player.
But Lennon - being the man he is - will also be asking questions of himself and his own judgement.
He has worked very hard to build a reputation in management, and is only too aware how every decision he makes is analysed and criticised, as he puts it: "To the nth degree".
No-one is suggesting Griffiths is a lost cause, beyond redemption, or a bad apple, of which we all know it only takes one.
But, even for a boss who has had to manage a number of other issues involving players and their behaviour away from the field, Griffiths could already represent the toughest challenge.
Lennon left him out of the starting XI at Tannadice, explaining he did so not as any kind of punishment, but because Griffiths had been carrying an ankle problem.
By the time the striker came on to the pitch as a replacement for Liam Henderson six minutes into the second half, United had started to finally get their disorganisation remedied and were gaining a foothold in the game.
The supporters of both clubs had been united in making Griffiths a cause celebre, chanting different versions of a song about him singing what he wants.
As he had warmed up in the first half, Griffiths wisely chose to ignore the dedicated soundtrack.
But, as he left the field at full-time, he finally succumbed and held his hands in the air in the manner shown when he was leading the singing in the Edinburgh pub.
It might ingratiate him with some. It could even earn him a kind of cult status with others.
But it is unlikely to endear him to the high-ranking personnel within the club which pays his wages - and that includes key figures above the manager.
More home truths will be delivered by Lennon.
And, while the headlines which claimed he was 'drinking in last chance saloon' following his original offence may have embellished somewhat the warning the manager actually announced last week, they might require to be dusted down again very soon.
Lennon would much rather be concentrating on the rehabilitation of Beram Kayal, given his chance against United, and showing that, when he wants to, he still can contribute to the team.
Likewise, Lennon would much prefer to be enjoying the renaissance of Samaras, whose display in the opening half hour against United was akin to a 'Best of Sami' DVD.
And there is no doubt the return to action, after rupturing an Achilles tendon, of nice guy Steven Mouyokolo, should have been something for everyone to celebrate.
Instead, Lennon's weekend has been marked - perhaps indelibly - by the display of one of his players a week earlier and in a pub, not a football pitch.